Screw-holding screw-driver.



'l l VEA/Tb@ i PATENTED MAR. 20,1900.

L. s. sTARRETT.

' SCREW HQLDING SCREW DRIVER.l

APPLIGATION FILED SEPT. 14. 1904.

a VintRov7S. erinnern-0F' Arno/L, MASSACHUSETTS; ASSieNoRXTo THE 'y Il..I s;l SrfnRiiT1-co,' lor" .arno-L, MASSACHUSETTS. n. Sorensen* f,,jTroN'@MASSACHUSETTS -f y I No. 815,758. 'speeieatictr intent. .rate-atea nareneo, "recta" Application filedv September 14, 1904.` Ser-ilalllflo."22433616.`

.beam-@Sammie'fuiaum et machinerie@ f 'T0 ctZZ" it grr-biagi] f I Beit known that I, LARoi S. SrA-RRETT, of :end ofe'achffin'ger is tilted outwardlyg-f- Re; 55

i Athol, in the county of 'Worcester and State` of Massachusetts, haveiinvcntedcertai'n ,newv

and useful Improvements in Screw-Holding Screw-Drivers, of which vth'e followingy is a specification.

This invention is designed to provide a screw-driver especially adapted for use by. Opticians, watchmakers, and others usingl very small screws which cannotv be readily y Vheld by the fingers or existing tools While being inserted.

My improvementfrnishes 'a screw-driver-v operated by one hand to pick up, hold, and insert by rotation very minute screws, while the operators other hand holds the watch or other article on .which he'is working.

In .the drawings, Figure 1 represents the best form of' my improved tool complete.

' Fig. 2 is a longitudinal section thereof. Y Fig.

3 is an enlargedsectional detail of the barrel,

. socket-piece, and clamping-nut. i Fig. 4 represents, similarly enlargedlthe spindle and bowed fingers removed fromthe barrel. Fig. 5 shows in perspective the vfingers detached.

10 represents the barrel or hollow'body of l the tool ,l preferably milled or otherwise roughened externally to facilitate rotation and tapered at one end. From this tapered end the spindle 11 projects, terminating in the bit 12,

- which enters the slot of' the screw-head.

.y The characteristic feature of this invention is the peculiar construction and operation of the pair of spring-fingers 13. Said fingers are preferablyformed from a single piece of elastic metal integral with a neck portion 14, severed onone side and having a sliding frictional fit on the spindle. Such fingers along their outer portions orl free ends lie normally parallel with and close-to the spindle with inwardly-tnrned tips vto engage v the screw, and their inwardportions near said neck are formed with integralV convex bows 15, theex'- tremitiesof which bear on-the interposed spindle, so that when'said bows are compressed Von the spindle the free ends of the fingers open out, so as to pick up or release a arch of each bow somewhat and the spindle screw. This peculiar action is illustrated in Fig. 4 in full and dotted lines, where it will be seen that inward pressure of the bows 15 t0- ward theinterposed spindle 11 f'lattens the leasing this pressure automatically closesit'lie fingersf 'At vschffulcrurr'r-'poinft 'Ifpreferably overstraining by any outward pressure at their l `tips when the bit of the spindle or head of a5 protruded between and beyond screw' is The spindle 11 ispreferably made detachable with the fingers 13 14 15 from the barrel I u 1 0 for conveniencein use for various purposes of the smaller but operative toolshown in Fig, 4, where the enlarged rear end 17 of 7o v the spindle may serve as a handle. The `barrel has, therefore,within its op en end a fixed internal socket piece 18, shaped vat its inner end to engage the fiattened terminus of the spindle to insure its rotationwiththe barrel. There 'is falso within the barrelA a longitudinally-slitted friction-'sleeve 19 to bear 'laterally on the inserted spindle to prevent it from dropping out. These two devices are prefer-` ably formed in one', as b est shown in Fig. 3, and combined witha clamping nut 20,"

adapted to screw upon the threaded exterior of the friction-prongs 19 and by aninternal beveled shoulder to tighten them upon the spindle.

I claim as my invention- .l 1. In a screw-driver, the Spindle with terminal bit, in combination with a pair of elastic fingers 13 connected by a neck 14 fitting adjustably on the Spindle, such yfingers at their'free ends `lying normally parallel withk the spindle and having inwardly-turned tips, and being formed near said neck with convex bows 15, the extremities of which, when compressed, bear onthe spindle and .open said tips,l substantially as set forth.

2'. In a screw-driver, the spindle with terminal bit, in comb'ination with a pair of elastic fingers connected'by a cylindrical neck in-A the spindle and serving, when compressed.

thereon, t0 spread or open out the free ends of the lingers, substantially as set forth.

` 3. In a screw-driver, the hollow barrel provided internally with a friotional device and lixed socket-piece, to respectively secure the spindle frietionally to and for rotation with the barrel, in combination with a spindle removable from said parts and with a pair of elastic lingers mounted thereon, such lingers having free ends normally parallel to the spindle, and convex bows the extremities of which bear upon the spindle, the tips of said lingers being adapted to be opened by oompression of the bows, substantially as set forth.

4. In a screw-driver, the spindle with a ter- LAROY S. STARRETT.

Witnesses:

WILLARD G. NIMs, FRANK E. WING. 

